Corneal Characteristics of Myopic Malay School Children and Their Association with Axial Length.

Introduction: Corneal characteristics are unique to each eye and can vary among different levels of refractive errors. However, minimal data are available in the literature on corneal characteristics in myopic Malay school children including the difference between the low myopic group and the moderate myopic group. Therefore, this study aims to determine the corneal characteristics of myopic Malay school children and their associations with axial length. Methods: A total of eighty-four data samples were extracted from forty-two myopic Malay school children. Measurements of the central corneal thickness (CCT), corneal curvature, corneal diameter, and axial length were measured using Lenstar LS900, a non-contact optical biometer. Data were later stratified by the spherical equivalent refraction (SER) into a low myopic group and a moderate myopic group, and paired t-test were employed to determine the differences in the corneal characteristics between these two groups. Univariate and multivariate linear regressions were performed to identify factors that are significantly associated with axial length. Results: There was no significant difference in the CCT, corneal curvature and corneal diameter between the low myopic group and the moderate myopic group (t82=0.015, P=0.99), (t82=-0.802, P=0.43) and (t82=-0.575, P=0.57), respectively. Pearson univariate correlation analysis found that axial length significantly correlated with corneal curvature (r=-0.765, P<0.001) and corneal diameter (r=0.614, P<0.001) but no significant correlation found with CCT (r=0.046, P=0.68). Multiple regression analysis showed that axial length was significantly associated with a flatter corneal curvature (P<0.001), older age (P<0.001) and larger corneal diameter (P=0.02). Conclusion: This study reported the corneal characteristics in myopic Malay school children and its associations with axial length. Results of this study can serve as a reference value for the myopic Malay schoolchild population.

Baseline Accommodation and Binocular Vision Measures in Malay Schoolchildren Enrolled in the Myopia Control Study Using Spectacle Lenses in Kuala Lumpur.

Myopia control lenses have been shown to modify visual function; however, it is arguable if these changes are short-term or long-term. We investigated the changes in accommodative behaviour and binocular vision functions of Malay myopic children who participated in a myopia control trial utilising spectacle lenses (n = 40). This article presents baseline accommodation and binocular vision measurements. The mean (± SD) age, spherical equivalent measured by cycloplegic autorefraction, and axial length (AL) for the right eyes were 10.00 ± 1.47 years, -3.02 ± 1.20 D, and 24.42 ± 0.93 mm, respectively. All participants had good distance and near visual acuities with high-contrast charts (100%), which were significantly better than low-contrast charts (10%) (p < 0.001). The mean (± SD) accommodative lag at baseline was 1.14 ± 0.35 D, while monocular and binocular accommodative amplitudes were 15.35 ± 2.07 D and 16.82 ± 2.27 D, respectively. Malay schoolchildren in this study were more esophoric at near compared to distance, with an accommodative-convergence over accommodation (AC/A) ratio of 5.64 ± 0.66 ∆/D. A higher degree of myopia was found to be associated with a longer AL (r = -0.49, p < 0.05) and higher esophoria at near (r = -0.46, p < 0.05). These baseline measures are consistent with data from other studies showing that myopic children have a high accommodative lag, an elevated AC/A ratio, a longer AL, and are more esophoric at near. The measures reported herein will serve as a basis for examining changes that occur within 12 months of wearing myopia control spectacle lenses.

Peripheral Eye Length Evaluation in Myopic Children Undergoing Orthokeratology Treatment for 12 Months Using MRI.

Purpose: To investigate changes in peripheral eye length (PEL) in myopic children undergoing orthokeratology (Ortho-K) treatment for 12 months using MRI. The results were compared to single vision spectacle wearers (SVS). Patients and Methods: A total of 70 children with myopia (aged 8-9 years old) were recruited. A total of 45 children were fitted with Ortho-K, and 25 were fitted with SVS. The PEL and axial length (AL) were measured by using MRI 3-Tesla, whereas central and peripheral refraction (PR) measurements were conducted at ±30 degrees horizontally with nasal (N) and temporal (T) intervals of 10°, 20°, and 30° and with an open field autorefractometer (WAM-5500 Grand Seiko). All the measurements were conducted at the baseline and 12 months. Results: The MRI analysis indicates that at 12 months, the SVS group showed more elongation of the PEL and AL at all eccentricities than the Ortho-K group did (p < 0.05). The Ortho-K group only showed significant PEL elongation beyond 20 degrees at N20, N30, T20, and T30 (p < 0.05); however, a significant reduction in the AL was detected in the center AL, N10, and T10 (p < 0.05). All eccentricities in the relative PR of the Ortho-K group were significantly more myopic than at the baseline (p < 0.05), whereas in the SVS group, all eccentricities in the relative PR were shown to be significantly more hyperopic than at the baseline (p < 0.05). The PEL and PR showed negative correlations at 12 months in the Ortho-K group. Conclusion: MRI analysis can be utilized to describe changes in PEL in myopic children. It appears that as myopia progressed in Ortho-K lens wearers, the PEL increased by a greater amount than the AL did; thus, the retina was reshaped to become increasingly oblate and to display peripheral myopic defocus.

Comparison of vision-related quality of life between wearing Orthokeratology lenses and spectacles in myopic children living in Kuala Lumpur.

PURPOSE: There are limited reports available on the impact of wearing Orthokeratology (ortho-K) lenses on the quality of life of Asian children. This study evaluated and compared vision-related quality of life (VRQoL) between myopic children wearing ortho-K lenses and single-vision spectacles (SVSs), living in Kuala Lumpur, using Paediatric Refractive Error Profile (PREP) questionnaires. METHODS: This is a cross sectional study. Myopic children who had been wearing ortho-K and SVSs for 12 months were recruited, and the questionnaires were distributed online. The PREP scores were obtained using a summary scoring method. The Shapiro-Wilk test was used to determine data normality. Unpaired t-test was performed for normally distributed data, and the Mann-Whitney test for non-normally distributed data. P < 0.05 was considered significant. RESULTS: A total of 70 subjects participated in this study (45 ortho-K and 25 SVSs), with a mean age of 10.86 ± 0.73 years. The mean scores for all the items were higher in ortho-K than SVS wearers (p < 0.05). With regard to symptoms during ortho-K lens wear at night, <10 % of the subjects reported difficulty falling asleep, itch/burning/dry eyes and foreign body sensation after lens insertion. CONCLUSION: Ortho-K improves the vision-related quality of life of myopic school children in Kuala Lumpur. Thus, it should be considered by more local optometrists when managing myopic children.

Ocular Dimensions, Refractive Error, and Body Stature in Young Chinese Children with Myopia in Kuala Lumpur, Malaysia.

Purpose: Eyeball shape varies with refraction and body stature. Nevertheless, there are few reports on three-dimensional measurements of eyeball shape in children. The aim of this cross-sectional observational study was to investigate the associations between three-dimensional measurements of ocular dimensions, refractive error, and body stature in young Chinese children with myopia in Kuala Lumpur. Materials and Methods: Thirty-five female and 35 male school children aged 8-9 years old were recruited in this study. Cycloplegic spherical equivalent (SE) and visual acuity (VA) were determined using a logarithm of the minimum angle of resolution (logMAR) chart. Body mass index (BMI), body height, and head circumference were ascertained. Three ocular dimensions, that is, longitudinal axial length (LAL), horizontal width (HW), and vertical height (VH), were determined using magnetic resonance imaging (MRI). Results: There were significant differences among the ocular dimensions in the myopic children. Bonferroni-corrected pairwise t-tests showed that LAL was significantly longer (mean difference, 0.318 mm) than VH, which was in turn significantly longer (mean difference, 0.245 mm) than HW. Body height was significantly correlated with LAL (p < 0.001) and SE (p < 0.001), and multivariate linear regression confirmed that longer LAL and more myopic SE were associated with increased body height (p < 0.001 for both) but not BMI (p = 0.894 and p = 0.413) or head circumference (p = 0.305 and p = 0.226). Conclusion: This study confirms previous reports that changes in ocular dimensions are associated with body height in young children. Axial elongation (forming a prolate profile) occurs in myopic children of both genders at a young age.

Ocular dimensions by three-dimensional magnetic resonance imaging in emmetropic versus myopic school children.

Background: Magnetic resonance imaging (MRI) has been used to investigate eye shapes; however, reports involving children are scarce. This study aimed to determine ocular dimensions, and their correlations with refractive error, using three-dimensional MRI in emmetropic versus myopic children. Methods: Healthy school children aged < 10 years were invited to take part in this cross-sectional study. Refraction and best-corrected distance visual acuity (BCDVA) were determined using cycloplegic refraction and a logarithm of the minimum angle of resolution (logMAR) chart, respectively. All children underwent MRI using a 3-Tesla whole-body scanner. Quantitative eyeball measurements included the longitudinal axial length (LAL), horizontal width (HW), and vertical height (VH) along the cardinal axes. Correlation analysis was used to determine the association between the level of refractive error and the eyeball dimensions. Results: A total of 70 eyes from 70 children (35 male, 35 female) with a mean (standard deviation [SD]) age of 8.38 (0.49) years were included and analyzed. Mean (SD) refraction (spherical equivalent, SEQ) and BCDVA were -2.55 (1.45) D and -0.01 (0.06) logMAR, respectively. Ocular dimensions were greater in myopes than in emmetropes (all P < 0.05), with no significant differences according to sex. Mean (SD) ocular dimensions were LAL 24.07 (0.91) mm, HW 23.41 (0.82) mm, and VH 23.70 (0.88) mm for myopes, and LAL 22.69 (0.55) mm, HW 22.65 (0.63) mm, and VH 22.94 (0.69) mm for emmetropes. Significant correlations were noted between SEQ and ocular dimensions, with a greater change in LAL (0.46 mm/D, P < 0.001) than in VH (0.27 mm/D, P < 0.001) and HW (0.22 mm/D, P = 0.001). Conclusions: Myopic eyeballs are larger than those with emmetropia. The eyeball elongates as myopia increases, with the greatest change in LAL, the least in HW, and an intermediate change in VH. These changes manifest in both sexes at a young age and low level of myopia. These data may serve as a reference for monitoring the development of refractive error in young Malaysian children of Chinese origin.

Effect of Smoking on Tear Stability and Corneal Surface.

PURPOSE: To determine the effect of smoking on tear stability and ocular surface of the cornea among students aged between 19 and 25 years. This study also aimed to find a correlation between tear film stability with a score of McMonnies Dry Eye Questionnaire (MDEQ) and Ocular Surface Disease Index Questionnaire (OSDI). METHODS: This is a prospective, non-interventional, comparative study of 59 male (27 smokers and 32 non-smokers) undergraduates of a public university. Tear film stability was evaluated using non-invasive tear break-up time and fluorescein tear break-up time. Corneal staining was determined using Efron grading scale. MDEQ and OSDI Questionnaires were used to assess dry eye symptoms. Data were obtained from the right eye only and analyzed using descriptive and correlation analysis. RESULTS: The age range of the participants was between 19 and 25 years. The mean age for smokers and non-smokers was 22.19 ± 2.20 and 21.22 ± 1.83 years, respectively (P = 0.07). The smoker group had statistically significant lower tear film stability than the non-smoker group (P < 0.0001). Corneal staining was statistically significant higher at the nasal and temporal parts of the cornea in smokers (P < 0.05). There was a moderate correlation between tear film stability and scores of MDEQ and OSDI. CONCLUSIONS: Tobacco smoke has a significant effect on the tear film stability, seen in reduced tear stability values among smokers. Corneal staining was found to be more extensive in the smokers. These findings would be useful to eye-care providers in the management of their dry eye patients related to smoking.

Refractive error, visual acuity, and corneal-curvature changes in high and low myopes with orthokeratology treatment: A Malaysian study.

BACKGROUND/PURPOSE: The effect of orthokeratology (OK) on low myopia is well known, but there are a few reports on its effect on high myopia. In this study, the parametric changes in high and low myopia as results of wearing OK lenses for a period of 6 months have been analyzed. METHODS: Records of schoolchildren (age 7-17 years) undergoing OK treatment from an optometry clinic were retrospectively reviewed. Data involving refractive errors, uncorrected visual acuity, and corneal curvatures at baseline and after 1 day, 1 week, 1 month, 3 months, and 6 months of OK treatment from 25 patients who fulfilled the inclusion criteria were examined. For the analysis, the participants were arbitrarily divided into two groups comprising high myopia (< -6.00 D) and low to moderate myopia (from -1.00 D to -6.00 D). RESULTS: Significant reductions of refractive error, improvement in visual acuity, and corneal-curvature flattening were found in all participants after 6 months of OK lens wear compared to the baseline. No significant changes were found in corneal toricity in both high and low to moderate myopic groups. Almost all of these occurred after one night of lens wear in both the high- and low-myopia groups. CONCLUSION: The OK lens wear significantly reduced the refractive error and corneal curvature that results in the improvement in visual acuity in both high- and low-myopia groups, and the reduction seemed to occur nearly at the same time despite the difference in initial myopic power. High myopes with refractive power up to -8.25 D would benefit significantly from OK lenses.

Effects of wink glass on blink rate, nibut and ocular surface symptoms during visual display unit use.

PURPOSE/AIM: Wink glass (WG), an invention to stimulate blinking at interval of 5 s was designed to reduce dry eye symptoms during visual display unit (VDU) use. The objective of this study is to investigate the effect of WG on visual functions that include blink rate, ocular surface symptoms (OSS) and tear stability during VDU use. MATERIALS AND METHODS: A total of 26 young and asymptomatic subjects were instructed to read articles in Malay language with a computer for 20 min with WG whereby their blink rate, pre- and post-task tear break-up time, and OSS were recorded. The results were compared to another reading session of the subjects wearing a transparent plastic sheet as a control. RESULTS: Non-invasive tear break-up time was reduced after reading session with transparent plastic sheet (pre-task = 5.97 s, post-task = 5.14 s, z = -2.426, p = 0.015, Wilcoxon), but remained stable (pre-task = 5.62 s, post-task = 5.35 s, z = -0.67, p = 0.501) during the reading session with WG. The blink rate recorded during reading session with plastic sheet was 9 blinks/min (median) and this increased to 15 blinks/min (z = -3.315, p = 0.001) with WG. The reading task caused OSS (maximum scores = 20) with median score of 1 (0-8) reduced to median score of 0 (0-3) after wearing WG (z = -2.417, p = 0.016). CONCLUSION: WG was found to increase post-task tear stability, increased blinking rate and reduced OSS during video display unit use among young and healthy adults. Although it may be considered as an option to improve dry eye symptoms among VDU users, further studies are warranted to establish its stability and its effect on subjects with dry eyes.

Anterior segment parameters in Indian young adults using the Pentacam.

To evaluate Pentacam-Scheimpflug imaging of anterior segment parameters in young Indian adults. In this prospective study 120 eyes of 60 normal Indian subjects with a mean age of 25.93 ± 6.58 years (range 17-39 years) were assessed by Pentacam. Main outcome measures were central corneal thickness (CCT), thinnest corneal thickness (TCT), apex corneal thickness (apex CT), peripheral corneal thickness at 2, 4, 6 and 8 mm from the thinnest point, location of the thinnest pachymetry, corneal volume (CV), anterior chamber depth (ACD), anterior chamber volume (ACV) and anterior chamber angle (ACA). Independent samples t test, dependent samples t test, ANOVA and Pearson correlation test were used for statistical analysis. The mean CCT, TCT, Apex CT and CV were 544.95 ± 35.42, 542 ± 35.19, 545.43 ± 35.45 and 61.64 ± 4.17 µm, respectively. There was a gradual increase in CT from the thinnest point to the periphery. The mean ACD was 3.14 ± 0.33 mm, mean ACV was 177.77 ± 29.02 mm(3), and mean ACA was 39.36° ± 5.42°. There was no significant difference between CCT, TCT and Apex CT. A significant positive correlation was found between CCT and peripheral CT and also between anterior chamber parameters. TCT was mainly located in the inferotemporal and superotemporal zone. No significant difference was found in parameters between the right and left eyes and also between genders. This study provided information about a wide range of parameters in the anterior segment of healthy Indian eyes. These results could be helpful in assessment of patients with corneal diseases, glaucoma and screening for refractive surgeries.

Anterior segment characteristics of keratoconus eyes in a sample of Asian population.

PURPOSE: To assess changes in anterior segment parameters of keratoconus eyes at different stages of the disease in a sample of the Asian population. METHODS: Files of 32 patients (48 eyes) diagnosed as clinical keratoconus were assessed and the following parameters noted: central corneal thickness (CCT), thinnest corneal thickness (TCT), location of thinnest pachymetry, anterior chamber depth (ACD) at the centre from posterior corneal surface, ACD at 1, 2 and 3mm inferior-paracentral, ACD at thinnest pachymetry, anterior chamber volume (ACV) and anterior chamber angle (ACA). For analysis, keratoconus eyes were classified into 3 subgroups according to mean keratometry readings (mild: K≤47.0D, moderate: 47.0

Corneal thickness and volume in subclinical and clinical keratoconus.

To evaluate corneal thickness and volume in subclinical and clinical keratoconus in Asian population with the aim of discriminating between normal and ectatic cornea. Eyes were placed into one of the following three groups: normal, subclinical, and mild-moderate keratoconus. Pentacam Scheimpflug imaging (Oculus Inc., Wetzlar, Germany) was performed for each participant to record thinnest corneal thickness, central corneal thickness, corneal volume (CV), peripheral corneal thickness (PCT) and percentage thickness increase (PTI) at 2, 4, 6, and 8 mm. The data were exported to SPSS for statistical analysis. Subjects comprised 52 normal, 15 subclinical keratoconus, and 32 mild-moderate clinical keratoconus eyes. Our results indicated that corneal thickness (CT) distribution, PTI, and CV in normal eyes were significantly different compared with subclinical and clinical keratoconus (P < .05). Overall, subclinical group exhibited lower CT distribution and volume, and higher PTI in comparison with normal eyes. However, they showed higher CT distribution and volume, and lower PTI compared with keratoconus group. In addition, there was a smaller change in PCT and PTI from the thinnest point of the cornea to the periphery. The results of the present study indicate that CT parameters and CV were significantly different in normal versus subclinical group and in normal versus keratoconus group. These findings could help clinicians to better discriminate between normal and ectatic cornea.

Grading of tarsal conjunctiva of young adults in Malaysia.

BACKGROUND: The monitoring and assessment of the upper tarsal conjunctiva can be enhanced by the use of a grading scale. The aim of this study was to categorise the appearance of normal tarsal conjunctiva among young adults in Malaysia using the Institute for Eye Research grading scale and to investigate inter- and intra-observer agreement. METHODS: The appearance of the upper tarsal conjunctiva of 416 non-contact lens wearing subjects aged between 19 to 24 years was assessed by two separate observers for roughness and redness in three separate zones using the Institute for Eye Research grading scale. The average grade for each zone and overall grade for roughness and redness were calculated. Inter- and intra-observer agreements were analysed. RESULTS: Subjects were categorised for ethnicity and the roughness and redness were calculated. No significant differences were found between Malay and Chinese eyes (p > 0.05). The average grades for the upper tarsal conjunctiva redness and roughness were 0.90 ± 0.25 and 0.86 ± 0.43, respectively. Significantly higher roughness scores were found in zone 1 compared to the other two zones (p = 0.03). Significant association was also found between tarsal conjunctiva redness and roughness (Spearman ρ= 0.45, p < 0.001). Correlation between redness and roughness with age (p = 0.48, p = 0.65) and gender (p = 0.30, p = 0.79) were not significant. Only 2.2 per cent of subjects had scores higher than 2.0 for roughness or redness. Inter- and intra-observer analysis showed good agreement between two observers during the study. CONCLUSION: The roughness and redness of normal tarsal conjunctiva among young adults in Malaysia were found to be less than two units. Results of this study might be beneficial in clinical trials using contact lenses where changes in the tarsal conjunctiva are commonly used as an outcome measure.

The resin-embedded cornea prepared via rapid processing protocol : a good histomorphometric target for clinical investigation in ophthalmology and optometry.

This study illustrates and quantifies the changes on corneal tissue between the paraffin-embedded and resin-embedded blocks and thus, selects a better target in investigational ophthalmology and optometry via light microscopy. Corneas of two cynomolgus monkeys (Macaca fascicularis) were used in this study. The formalin-fixed cornea was prepared in paraffin block via the conventional tissue processing protocol (4-day protocol) and stained with haematoxylin and eosin. The glutaraldehyde-fixed cornea was prepared in resin block via the rapid and modified tissue processing procedure (1.2-day protocol) and stained with toluidine blue. The paraffin-embedded sample exhibits various undesired tissue damage and artifact such as thinner epithelium (due to the substantial volumic extraction from the tissue), thicker stroma layer (due to the separation of lamellae and the presence of voids) and the distorted endothelium. In contrast, the resin-embedded corneal tissue has demonstrated satisfactory corneal ultrastructural preservation. The rapid and modified tissue processing method for preparing the resin-embedded is particularly beneficial to accelerate the microscopic evaluation in ophthalmology and optometry.

Visual and binocular status of Down syndrome children in Malaysia.

BACKGROUND: Down syndrome is a common chromosomal anomaly. Few reported studies make reference to the ocular status in Asian children with Down syndrome. The purpose of this study was to determine the visual and binocular status of a sample of Down syndrome children in Malaysia. METHODS: A total of 73 Malaysian children with Down syndrome (38 boys and 35 girls) in the Kuala Lumpur area aged one to 12 years were examined. Cycloplegic refraction was performed on each eye and binocular visual acuity was assessed using the Cardiff acuity card or the LogMAR chart. Binocular functions were assessed using the cover test and Lang's stereo acuity test. RESULTS: The mean age of the subjects was 6.01 +/- 3.41 years. Refraction of the right eye showed that 10 per cent of the subjects were myopic, 20 per cent were hyperopic and 70 per cent had no significant refractive error. The mean spherical equivalent was +0.92 +/- 2.32 DS for the right eye and +0.99 +/- 2.21 DS for the left. The mean of binocular LogMAR VA was 0.36 +/- 0.22 (6/12). Cover test revealed that 21 subjects had strabismus (of those, 33 per cent had unilateral esotropia, 52 per cent had alternating esotropia, nine per cent had unilateral exotropia and five per cent had alternating exotropia). Only 22 subjects gave clear positive response to the stereotest. Other ocular findings included ptosis (one per cent), abnormal head posture (seven per cent) and nystagmus (six per cent). CONCLUSION: Malaysian children with Down syndrome have a high incidence of refractive error and strabismus. Regular visual examination is important so that corrective lenses can be prescribed to improve vision and to enhance the quality of life of these children in Malaysia.

Undercorrection of myopia enhances rather than inhibits myopia progression.

The effect of myopic defocus on myopia progression was assessed in a two-year prospective study on 94 myopes aged 9-14 years, randomly allocated to an undercorrected group or a fully corrected control group. The 47 experimental subjects were blurred by approximately +0.75 D (blurring VA to 6/12), while the controls were fully corrected. Undercorrection produced more rapid myopia progression and axial elongation (ANOVA, F(1,374)=14.32, p<0.01). Contrary to animal studies, myopic defocus speeds up myopia development in already myopic humans. Myopia could be caused by a failure to detect the direction of defocus rather than by a mechanism exhibiting a zero-point error.

Non-invasive tear break-up time in normal Malays.

BACKGROUND: Tear stability in normal Malays with consideration of gender and age has not been reported. In this study, we measured tear stability in normal Malays using the non-invasive tear break-up time (NIBUT). METHODS: Forty-eight Malay subjects aged seven to 60 years were recruited from among the staff, their children and students of the faculty. NIBUT was measured by noting the time taken for distortions to appear in a reflected image of a grid pattern formed on the corneal surface. RESULTS: The mean NIBUT of the sample was 15.8 +/- 9.4 (SD) seconds. The median was 14.6 seconds with range of 4.2 seconds to 48.6 seconds. The majority (73 per cent) of subjects had NIBUT values between six and 20 seconds. There was no significant difference in NIBUT values between males and females but there was a decrease of NIBUT with age. CONCLUSION: The NIBUT values found in this study are comparable to those reported for Asian populations but much less than those of Western populations. Our findings point to the need for local clinical studies in contact lens and contact lens-related research as tear physiology of the local population may not be the same as in Western populations.

Profile of a low vision clinic population.

BACKGROUND: Causes of low vision and types of low vision devices (LVDs) prescribed in other low vision clinics have been studied extensively. Similar studies have not been conducted in Malaysia. This paper reports the results of a retrospective study of 573 patients seen at the Universiti Kebangsaan Malaysia-Malaysian Association for the Blind (UKM-MAB) low vision clinic in Kuala Lumpur. METHODS: The record cards of 573 patients seen at the UKM-MAB clinic over 10 years were examined and the following information extracted: date of first consultation, age, sex, cause of visual impairment as diagnosed by an ophthalmologist and types of low vision devices (LVDs) prescribed. RESULTS: The majority of patients were from the younger age groups with 423 (73.8 per cent) less than 50 years of age. Three hundred and ninety-five (68.9 per cent) of the subjects were males and 178 (31.1 per cent) female. The main causes of low vision were congenital structural defects including nystagmus among patients in the zero to 29 years age group, retinitis pigmentosa among the 30 to 59 years age group and age-related macular degeneration (ARM) among those over 60 years of age. CONCLUSIONS: Since the majority of the patients were from the younger age group the main causes of low vision were congenital and hereditary diseases. Three hundred and forty-one (59.5 per cent) patients seen at the low vision clinic accepted the use of LVDs.